The pre-print journal arXiv was used by Stephen Hawking’s former colleagues to publish his final paper. Only a few days before Hawking’s death in March the team managed to complete his research. This one was only the third in a series of papers which dealt with a concept that puzzled the great scientists for decades: the black hole information paradox.
It involves the extreme denseness of black holes, these objects capable of warping time-space which form when gigantic stars collapse within themselves or when two stars collide onto each other. The classical view of physics regarding black holes told us that nothing, not even light, could escape their grasp.
However, Hawking proposed back in the 70s that it is possible for black holes to have temperature and they could slowly release quantum particles. This effect, now named in his honor the ‘Hawking radiation’ would mean that even black holes would eventually fade away as it would leave behind a big nothing of a vacuum which would look the same for every black hole, regardless of what it ‘ate’ during its lifetime.
This incredible idea posed an issue, however. Where does all the information that a black hole swallowed in the form of celestial objects go? It is basic physics that tells us that no information can ever be lost. If the past had information, then we should be able to find it again. That’s the paradox that troubled Hawking.
The new paper showed that Hawking, together with his team, discovered a mechanism that can count the information carried by soft hairs – they are made of photons or gravitons (hypothetical particles of gravity). Naturally, this mechanism isn’t based on fully proven assumptions. However, it would agree with the Hawking’s equation which can even be found on the late scientist’s headstone, describing how black holes are capable of emitting Hawking radiation.